Variable speed paper feeding drive



4 Sheets-Sheet 1 FIG. I

\ INVENTOR. ALBERT M. GRASS ATTO R N EYS A. M. GRASS March 20, 1962Filed March 22, 1960 BY KERWAY, JENNEY. WITTER an HIlDREIH March 20,1962 GRASS 3,026,011

VARIABLE SPEED PAPER FEEDING DRIVE Filed March 22, 1960 4 Sheets-Sheet 2INVENTOR. ALBERT M. GRASS BY KENWAY, JENNEY, WITI'ER & HHDRETH ATTORNEYS March 20, 1962 A. M. GRASS 3,026,011

VARIABLE SPEED PAPER FEEDING DRIVE Filed March 22, 1960 4 Sheets-Sheet 3FIG. 4 I00. 28

MMfSEC 34 .25 MM/SEC. so. ham/550 x 5s 5s 25 MM/SEC s MM/SEC 5o 50 5e 5e50 50 IO. MM/sEc\ xv/1.0 MM/SEC.

2.s MM ISEC.

INVENTOR. ALBERT M. GRASS BY IENWAY. TENNEY. WITTFR z Hnnnrm ATTORNEYSMarch 20, 1962 A. M. GRASS 3,026,011

. VARIABLE SPEED PAPER FEEDING DRIVE Filed Mafch 22, 1960 4 Sheets-Sheet4 FIG. 6

FIG. 7

INVENTOR. ALBERT M. GRASS Y M,) w7, JW

ATTORNEYS 3,026,611 VARIABLE SPEED PAPER FEEDING DRIVE Albert M. Grass,101 Old Colony Ave, Quincy, Mass. Filed Mar. 22, 1960, Scr. No. 18,46415 Claims. (til. 22617S) This invention relates to a novel and improvedvariable speed paper feeding mechanism for recording instruments. Thisapplication is a continuation-in-part of my copendmg application SerialNo. 799,992, filed March 17, 1959 now abandoned. In recordinginstruments wherein a continuous recordmg is made on a moving chart orpaper, it is often desirable or necessary to change the speed of advanceof the paper or chart to vary the presentation of the record. Anexernplary prior attempt to provide a satisfactory variable speed paperdrive involves the use of a gear train having a plurality of drivengears continuously rotating at different speeds with the entire trainbeing mounted for indexing as a unit to connect a selected one of thedriven gears to a drive mechanism for advancing the paper and thus toadvance the paper at a selected speed. Such a device requires that thegear train be disconnected from the paper advance mechanism and/or themeans driving the gear train in order for the gear train to be indexed,as a unit, to a different position corresponding to the desired speed.As is Well known, whenever gears, splines and the like are disengaged,particularly if one of the gears is moving, attempted reengagement ofthe gears is often impeded or prevented by interference between theteeth of the gears. Further, the meshing of stationary gear with amoving gear may result in damage to the gears, thus often requiring thatthe drive motor of a device such as described be completely stoppedduring a speed change operation. This attendant loss of time, and thus aportion of a record during a recording, is undesirable.

Accordingly, it is the primary object of this invention to provide anovel and improved variable speed paper feeding device which permitschanges in the speed of paper advance without necessitating thedeenergizing of the drive motor for the device and without disconnectingthe speed change mechanism from the drive motor.

It is a further object of this invention to provide a novel and improvedvariable speed paper feeding device of the type described having noveland improved means for disengaging the drive motor from the paper duringa change in speed of paper advance.

An appreciation of the advantages of the invention as well as a detailedunderstanding of the structure of a specific embodiment thereof may behad from the following description taken in connection with theaccompanving drawings, in which:

FIG. 1 is a cross sectional view with certain parts removed in theinterest of clarity, of a recording instrument incorporating a variablespeed paper drive constructed in accordance with this invention;

FIG. 2 is a fragmentary cross sectional view substantially along theline 2-2 of FIG. 1;

FIG. 3 is a fragmentary cross sectional view substantially along theline 3-3 of FIG. 1;

FIG. 4 is a fragmentary cross sectional view substantially along theline 4-4 of FIG. 1;

FIG. 5 is a fragmentary cross sectional view substantially along theline 55 of FIG. 1;

FIG. 6 is a fragmentary cross sectional view similar to FIG. 1illustrating an alternative embodiment of the means for disengaging thedrive motor and paper during a change in speed of paper advance; and

FIG. 7 is a fragmentary cross sectional view substantially along thelines 77 of FIG. 6.

With reference to the drawings, and particularly FIG.

1, there is shown a recording instrument including a casing 10 generallycomprising side walls 11 and 12 and a bottom wall 13. The side wallssupport a top plate or wall 14, along which it is desired to advance apaper or chart 15. In the interest of brevity and as it is not necessaryfor a complete understanding of the invention, the mechanism forrecording a measurement or the like on the paper has not been shown. Abracket 16 secured to the bottom wall 13 supports a pair of spaced apartparallel mounting plates 18 and 20. The front plate 18 supports anelectric drive motor 22 having a drive pinion 24 drivingly engaging anidler gear 26 rotatably supported by the plate 18. A gear box 28 isdisposed between the plates 18, 2t) and is mounted for movement with acentral shaft 30 rotatably mounted in bushings supported by the plates18 and 20. The gear box comprises a pair of circular plates 32, 34secured to the shaft 30 on opposite sides of an enlarged portion of theshaft which spaces the plates 32, 34 in parallel relationship. A driveroller shaft 36 is supported by ball hearings on the plates 32, 34 withthe shaft 36 extending in parallel radially spaced relation to the shaft30. The roller shaft 36 carries a driven gear 38 disposed externally ofthe gear box 28 and engageable with an idler gear 40 rotatably carriedby the plate 34. The idler gear 40 is engageable with a gear 42coaxially received over the shaft 30 and rotatably mounted thereon by abushing. A gear 44 is mounted coaxially of the gear 42 for rotationtherewith relative to the shaft 30 and is engageable by the idler gear26, previously described, whereby the motor drive pinion 24 will, uponenergizing of the motor, rotate the drive roller shaft 35.

The drive roller shaft 36 mounts a drive roller 46, externally of thegear box 28, for rotation with the shaft 36. The roller is partiallyreceived in an aperture in the top plate 14 wherein it is drivinglyengageable with the underside of the paper 15. The periphery of theroller is preferably provided with a surface conducive to good drivingengagement with the paper, such as by knurling the roller, or by othersuitable means. The paper is normally held down in firm engagement withthe drive roller 46 by pressure roll means 48, to be described in detailhereinafter.

As most clearly shown in FIG. 3, the gear box 28 carries a plurality ofadditional drive rollers 46' similar to the drive roller 46 justdescribed, with the rollers 46 and 46 being circularly arrangedconcentrically about the axis of the shaft 30. With particular referenceto FIG. 4, each of the rollers 46' is mounted on a shaft 50 rotata-blysupported in hearings on the plates 32, 34 and extending between theplates. Each of the shafts 50 carries a pair of gears 52, 54 fixedthereto and disposed between the plates 32, 34, with the exception ofthe shaft next adjacent the shaft 36 and to the right thereof, as viewedin FIG. 4. A plurality of idler gear shafts 56 are rotatably supportedon hearings on the plates 32, 34, and each of the idler shafts carries apair of gears 58, 60 fixed thereto and disposed between the plates 32,34. The idler gear shafts are circularly arranged concentrically aboutthe shaft 30, with each shaft 56 being disposed generally between a pairof next adjacent drive roller shafts St The drive roller shaft 36 has agear 62 fixed thereon which is engageable with the idler gear 58 nextadjacent thereto in a counterclockwise direction, as viewed in FIG. 4;and the associated idler gear 60 is engaged with the gear 52 on thedrive roller shaft 50 next adjacent thereto in a counterclockwisedirection, as viewed in FIG. 4. The other gear 54 of this drive rollershaft is engaged with the idler gear 58 of the next adjacent idler gearand so on in a counterclockwise direction until the last idler gear 60is reached, this last idler gear 60 being meshed with a single gear 64on the last drive roll shaft 59 in the train. In the specific embodimentshown, the ratios between the various pairs of meshed gears has beenselected to provide a speed reduction through the train of from 100 mm.per second peripheral speed at the drive roller 46 to a peripheral speedof .25 mm. per second at the last drive roller in the train. It is, ofcourse, to be understood that these values are purely by way of exampleand that the speed of the various rollers could be selected and variedfrom one to the other as desired for any particular use merely byselecting the proper gear ratios in the train.

Turning back to FIG. 1, it can be seen that the shaft 30 is axiallybored and slidably receives and supports an indexing shaft 66 extendingout of the right end of the shaft 30 and at its free outer end slidablyand rotatably supported by a bushing on the side wall 11 of the casing10. Fixed to the shaft 66 adjacent the right end of the shaft 30 is amale coupling member 68 having keys 70 extending longitudinally of theshaft 30 and drivingly engaged in slots 72 in the adjacent end of theshaft 30. The ends of the keys 76 are preferably spaced from the innerend of the slots 72 to permit leftward movement of the shaft 66 relativeto the shaft 30, as viewed in FIG. 1. As will be apparent, rotation ofthe shaft 66 will result in rotation of the ear box 28 about the axis ofthe shaft 36 to position a different one of the drive rollers inregistry with the underside of the paper so as to vary the speed ofadvance of the paper. A knob or handle 69 is fixed to the rightward endof the shaft 66 which projects outwardly of the casing 10, and the knobis preferably provided with suitable indicia to indicate the variouspaper speeds obtainable.

It should be noted that during rotation of the gear box no portion ofthe drive gear train is disconnected from another portion thereof orfrom the drive motor 22. In this connection, during rotation of theshaft 66, and thus the gear box 28, the idler gear 46 carried by thegear box will be revolved about the axis of the gear 42 engagedtherewith in planetary fashion.

The shaft 66 is biased in a rightward direction, as viewed in FIG. 1, bya compression spring '74 engaged between a pin on the connector 68 andthe end of a split collar 76 clampingly engaging a bushing 78 on theshaft 30. The collar 76 and bushing 78 form a part of an indexing camassembly most clearly shown in FIG. 5. The bushing 78 is slotted at oneend to provide a plurality of cantilever fingers 81} which clampinglyengage the shaft under the influence of the collar 76. As shown in FIG.1, the bushing mounts an indexing cam 82 for movement therewithcoaxially of the shaft 39. As shown in FIG. 5, the cam 82 has agenerally scalloped periphery including a series of promontories andvalleys, with the number of valleys corresponding to the number of driverollers on the gear box 23. An arm 84 is pivotally mounted at one end onthe front plate 18 and carries intermediate its ends a cam roller orfollower 86 engageable in the valleys of the cam 82 and a spring 88urges the cam follower into cam engagement. As will be apparent fromFIGS. 1 and 5, the cam 82 is angularly positioned relative to the shaft36 so that when the cam roller 86 is engaged in one of the valleys ofthe cam, one of the drive rollers of the gear box 28 will be positionedfor driving engagement with the paper.

With reference to FIGS. 1 and 2, the pressure roll mechanism will now bedescribed. The leftward end of the shaft 66, as viewed in FIG. 1,projects through the rear plate 2.0 and mounts a cam 96 for movementtherewith. The cam 96 is circular in plan and has a frusto-conicalperipheral surface 92 arranged coaxially of the shaft 66 and taperingtoward the leftward end of the shaft 66. A cam follower 94- is slidablyreceived in a recess in the plate 26 for movement generally radially ofthe shaft 66. The follower 94 includes a roller 96 engaging the conicalsurface of the cam 90 so that in response to leftward movement of theshaft 66 the cam M! will raise the cam follower 94. The follower 94 isprovided with a recess in its upper end in which is received the reduceddiameter lower end of a plunger Q8 extending through an opening in thetop plate 14 and having a lip or flange at its upper end normallyresting on the top wall 14. An arm 166, pivoted at one end, is supportedon the casing it) and extends generally parallel to the upper side ofthe top plate 14. A screw 162 threadably extends through the arm Mid andis engageable with the upper end of the plunger 98. The arm 1% rotatablymounts a pressure roll 164 having an axis extending parallel to the axisof the shaft 36). The roll 164 is engageable with the upper surface ofthe paper 15 to firmly engage the paper with a drive roller underneaththe paper, and a spring 106 urges the arm 1% and thus the pressure roll164 toward the paper.

It should be noted that the cam 99 also serves as a locking plate forthe shafts 66 and 36. In this connection, it may be seen in FIGS. 1 and2 that the cam M) has a plurality of openings 108 circularly arrangedconcentrically of the shaft 66. A pin 110 on the plate 20 is engageablein an opening 108 registering therewith to lock the shafts 66 and 30against angular movement when the shaft is in its rightward position asviewed in FIG. 1. The openings 168 correspond in number to the number ofdrive rollers on the gear box 28, and the cam is angularly positioned onthe shaft 66 so that with the cam roller 86 of the shaft indexingassembly engaged in a valley of the indexing cam 82 the pin 110 will bealigned with one of the openings 108.

In the operation of the device just described, when it is desired tochange the speed of paper advance, the shaft 66 is pressed inwardly ofthe casing 10 to move the cam 90 to the left, as viewed in FIG. 1, todisconnect the cam from the pin 110 and free the shafts 30 and 66 forrotation. At the same time, the cam will raise the cam follower 9 andthus the plunger 93, to pivot the arm 16%) in a counterclockwisedirection as viewed in FIG. 2 to lift the pressure roll 1G4 andeffectively disengage the paper and drive roller. The shafts 66 and 36may then be rotated to the desired angular position corresponding to thepaper speed desired, whereupon the indexing cam and roller will hold theshaft 30 in its new angular position. Upon release of the shaft 66, thespring 74 will return the shaft to its rightward position, whereupon thepin 116 will be engaged in the proper opening 108 of the cam 90 to againlock the shafts 66 and 30 against rotation.

As noted before, during the speed change operation, none of the drivegearing of the device is disconnected so as to eliminate any necessityfor reengaging relatively moving elements. Accordingly, if desired, thepaper speed may be changed without deenergizing the motor 22. Thisfeature permits adjustment of paper speed without any significant lossof record in a continuous recording operation. Where a low speed paperadvance is contemplated, say on the order of 1 mm./sec., it will beapparent that if the drive roller had to be disengaged from the geartrain in order to adjust the paper advance, and if the mating parts onthe drive roller and gear train were out of alignment when reengagementwas attempted, it might take several minutes before the matingbecamerealigned so at to permit reengagement thereof and continuation of therecording. The variable speed drive of this invention obviouslyeliminates any such undesirable delay. Further, it should be noted thatthe automatic disengagement of the paper and drive roller immediatelyprior to adjustment of the gear box assures that during adjustment ofthe gear box the paper will not become jammed between the pressure rolland drive rollers or be forced in a direction opposite the normaldirection of paper advance. A variable speed paper drive constructed inaccordance with this invention will thus provide the accurate andreliable service necessary for recording instruments While at the sametime is relatively simple and economical and is of rugged constructionto provide an extended trouble-free service life.

With reference to FIGS. 6 and 7, there is shown an alternative means fordisengaging the pressure roll for the paper during a speed changeadjustment of the gear box and also for releasably holding the gear boxin a desired angular position. The mechanism of FIGS. 6 and 7 performsthe combined functions of the indexing earn assembly of FIG. 5 and thepressure roll disengaging and gear box locking mechanism of FIG. 2. Aswill be seen from the following, the mechanism of FIGS. 6 and 7accomplishes the disengagement of the pressure roll in response toinitial rotation of the indexing shaft 66 and eliminates the need formoving the shaft axially of itself prior to rotating the shaft to indexthe gear box and effect a change in the speed of paper advance. Indescribing this aspect of the invention like reference numerals will beused in connection with parts which are similar to the parts previouslydescribed in connection with the device of FIGS. 1-5.

A cam 120 is fixed on the end of the indexing shaft 66 projectingoutwardly of the end of the shaft 30 and beyond the mounting plate 20.As shown in FIG. 7, the periphery of the cam is provided with aplurality of notches or recesses 122 and promontories 124. The recesses122 correspond in number and angular orientation to the drive rollers. Acam follower 126 is mounted on the frame of the device for verticalmovement radially of the cam. The earn follower includes a roller 128which is engageable with the periphery of the cam 120. The follower 126also includes a spring biased plunger 13f extending upwardly from theupper end of the follower. The upper end of the plunger 130 engages thelower end of the screw 102 carried by the pivoted arm 160* which mountsthe pressure roll 104. It will be apparent that as the index shaft 30 isrotated from the position of FIG. 7, the cam follower 126 will ride outof a recess 122- and up onto a promontory 124 to disengage the pressureroll 1634 from any paper between the pressure roll and an underlyingdrive roller. Further rotation of the cam 12% by the index shaft 66 willcause the cam follower 126 to drop back into a recess 122 and effectlowering of the pressure roll into paper engagement under the influenceof the spring 106 biasing the arm 100.

A locking plate or cam 132 is fixed on the end of the shaft 30 and isdisposed between the cam 126 and mounting plate 20. As most clearlyshown in FIG. 7, the locking plate is generally circular and is providedwith a plurality of angularly spaced apart notches or recesses 134 inits periphery. The recesses 134 correspond in number and angularorientation to that of the drive rollers of the device. The cam follower126, as shown in FIG. 6, has a depending projection 136 which isreceivable in the notches 134 of the locking plate. The projection 136is centered relative to the roller 128 in the sense that thelongitudinal center line of the projection passes through the axis ofthe roller and extends in the direction of movement of the follower.When the projection 134 is so received in a locking plate notch, thegear box 28 will be positioned angularly about the shaft 39 so that oneof the drive rollers is in registry with the pressure roll 104. In orderto provide the indexing drive for the gear box, the locking plate 132 isprovided with an elongated slot 138 which is generally centered relativeto one of the notches 134. The cam plate 120 mounts a pin 140 which iscentered relative to one of the recesses 122 in the cam and which isreceivable in the slot 138 in the locking plate. Inasmuch as the pin 140and slot 138 are both centered relative to one of the notches 122 and134 in the cam and locking plates respectively, it will be seen thatwhen the cam follower is engaged in one of the notches of the cam platethe pin 140 will be centered in the slot 138. As will be apparent, thepin and slot connection between the cam and locking plates provides alost motion driving connection between the indexing shaft 66 and gearbox 28.

When it is desired to index the gear box to change the speed of paperadvance, the index shaft 66 is rotated by the hand wheel 69. Initialrotation of the shaft 66 will cause rotation of the cam 12%. However,because of the lost motion connection between the cam and lockingplates, the gear box will not be moved until the cam has been rotatedsufficient for the pin to engage one end of the slot 138 in the lockingplate. The slot 138 is sufficiently long so that prior to engagement ofthe pin 146 with an end of the slot 138, the pressure roll 104 will havebeen disengaged from the paper. Further, rotation of the cam 120 in thesame direction will cause rotation of the locking plate 132. While theraising of the follower 126 will cause the projection 136 to be moved ina direction outwardly of a notch 134 in the locking plate, it ispreferred that the sides of the notches 134 be sloped outwardly of thenotches so that the sides of the notches will tend to cam the projectionupwardly and out of the notches. After the follower has been raisedsufiiciently the projection 136 will ride onto the periphery of thelocking plate between the notches and prevent downward movement of thefollower. After suflicient rotation of the locking plate, the projection136 will be in registry with another notch 134 and will be urged intothe notch by the spring 166 biasing the arm 1110 so as to lock the gearbox in a new position. As the projection moves into registry with anotch, the cam and locking plates will be angularly offset relative toeach other because of the lost motion drive therebetween. In thisconnection, the length of the slot 138 in the locking plate is selectedto provide that the total angular movement of the pin 140 from one endof the slot to the other end is less than the angular spacing of thecrests of next adjacent promontories on the cam plate. Accordingly, whenthe projection 136 is moved into registry with a notch, the roller 128will be angularly offset from a crest of a promontory on the cam 121)and in a direction opposite the direction of rotation of the cam plate.Therefore, as the projection 136 is moved into a notch on the lockingplate by the force of the spring 166, the roller 128 which is alsobiased by the spring 166, will tend to be moved into the cam platerecess 122 with which it is in partial registry. As the roller movesinto the recess it will cam the plate 120 in a direction opposite thedirection it had been turned and the pin 14% will again be centered inthe slot 138. Thus it can be seen that there has been provided means forsequentially disengaging the pressure roll from the paper, angularlyindexing the gear box, and re-engaging the pressure roll and paper allthrough operation of the index shaft 66 with the disengagement of thepressure roll being in response to initial operation of the shaft. Whilethe operation has been described with respect to rotating the shaft 66and gear box in one direction, it will be apparent that the shaft 66 maybe rotated in either of both directions of rotation with the sameresult.

Inasmuch as many changes could be made in the above construction andmany apparently widely different embodiments of this invention could bemade without departing from the scope thereof, it is intended that allmatter contained in the above description or shown in the accompanyingdrawings shall be interpreted as illustrative and not in a limitingsense.

It is also to be understood that the language in the following claims isintended to cover all of the generic and specific features of theinvention herein described and all statements of the scope of theinvention which, as a matter of language, might be said to falltherebetween.

I claim as my invention:

1. In a variable speed mechanism for advancing record paper and thelike, a gear box fixed against axial movement and mounted for rotationabout an axis and supportin a gear train, means to rotate said gear box,releasable means normally holding said gear box against rotation, aplurality of paper engageable drive rollers carried by the gear box andrespectively connected to different portions of said gear train, a gearmounted for rotation coaxially of the axis of the gear box and relativeto the gear box and said means to rotate the gear box, means to drivesaid gear including a drive gear engaged therewith, and means drivinglyconnecting the rst mentioned gear to said gear train including an idlergear rotatably mounted on said gear box and engaged with the firstmentioned gear so that upon rotation of said gear box about its axissaid idler gear will be revolved about the axis of said first gear topermit angular adjustment of the gear box about its axis withoutdisconnecting the drive rollers from said first gear.

2. In a variable speed mechanism for advancing record paper and thelike, a rotatable gear box supporting a gear train, a plurality of paperengageable drive rollers supported by the gear train, a rotatableindexing shaft disposed coaxially of the gear box and connected forrotation therewith, releasable means holding the shaft against rotation,a driven gear rotatably supported for rotation coaxially of the shaftand relative to the shaft and gear box, an idler gear mounted on thegear box for rotation about an axis extending in parallel spacedrelation to the axis of the first mentioned gear, the idler gear beingengaged with the first gear and being drivingly connected to the geartrain, means to drive the first gear, and means to selectively rotatesaid shaft whereby said idler gear will be revolved about the axis ofthe intermediate gear in planet gear fashion as the gear box is rotatedwith the shaft.

3. In a variable speed mechanism for advancing record paper and thelike, a rotatably mounted gear box supporting a gear train and carryinga plurality of paper engageable drive rollers connected respectively todifferent portions of the gear train, said gear box being rotatablethrough a plurality of adjusted positions in each of which positions aselected one of said rollers is in paper engageable position, a pressurerol-l supported for move ment toward and away from the axis of said oneof the rollers for firmly engaging a record paper with said one of therollers, and means operable to move said pressure roll away from saidone of the drive rollers and sequendaily to ro-tatably index said gearbox including a movable shaft, said means being operable to move saidpressure roll away from said one of the drive rollers in response toinitial movement of said shaft.

4. In a variable speed mechanism for advancing record paper and thelike, a rotatably mounted gear box supporting a gear train and carryinga plurality of paper engageable drive rollers connected respectively todifferent portions of the gear train, said gear box being rotatablethrough a plurality of adjusted positions in each of which positions aselected one of said rollers is in paper engageable position, a pressureroll supported for movement toward and away from the axis of said one ofthe rollers for firmly engaging a record paper with said one of therollers, means for rotating the gear box including an axially movableand rotatable shaft, and means connected to the pressure roll andresponsive to axial movement of the shaft to move said pressure rollaway from said one of the drive rollers.

5. In a variable speed mechanism for advancing record paper and thelike, a rotatably mounted gear box supporting a gear train and carryinga plurality of paper engageable drive rollers arranged about the axis ofthe gear box and connected respectively to different portions of thegear train, said gear box being rotatable through a plurality ofadjusted positions in each of which positions one of said rollers is inpaper engageable position, a pressure roll engageable with the oppositeside of paper engaged by said one of said rollers, means mounting thepressure roll for movement toward and away from said one of saidrollers, means urging the pressure roll toward said one of said rollers,and means to sequentially move the pressure roll away from said selectedone of said rollers and rotate said gear box including a rotatable andaxially movable shaft connected to the gear box for rotation therewithand for axial movement relative thereto, a cam on the shaft, and a camfollower operatively connecting the cam with the pressure roll.

6. In a variable speed mechanism for advancing record paper and thelike, a rotatable gear box supporting a gear train and carrying aplurality of paper engageable drive rollers respectively connected todiiferent portions of the gear train, a shaft mounted for rotation andfor axial movement, the shaft being connected to the gear box for axialmovement relative thereto and for rotation therewith through a pluralityof adjusted positions of the gear box in each of which positions one ofsaid drive rollers is in paper engageable position, a paper engageablepressure roll, a pivoted arm mounting the pressure roll for movementtoward and away from said selected one of said drive rollers, a springurging the pressure roll toward said one of said drive rollers, a cammounted on said shaft for axial movement therewith and having afrusto-conical cam surface arranged coaxially of said shaft, a camfollower engageable with said cam surface and connected to said arm sothat on movement of the shaft axially in one direction the pressure rollwill be moved away from said selected one of said rollers.

7. In a variable speed mechanism for advancing record paper and thelike, a rotatable gear box supporting a gear train and carrying aplurality of paper engageable drive rollers circularly arrangedconcentrically of the axis of the gear box and connected respectively todifferent portions of the gear train, said gear box being rotatablethrough a plurality of adjusted positions in each of which positions oneof said rollers is in paper engageable position, an indexing cam mountedfor rotation coaxially of and with the gear box and having a pluralityof separate surfaces on its periphery respectively corresponding inangular relationship about the gear box axis with said drive rollers, aspring biased cam follower engageable with said surfaces on the cam forresiliently holding the gear box in each of said adjusted positions,disconnectable means providing positive holding of the gear box in eachof said adjusted positions, and means to rotate the gear box including arotatable and axially movable shaft rotatively connected to the gear boxand connected to a portion of said disconnectable means to disconnectthe same in response to axial movement of the shaft.

8. In a variable speed mechanism for advancing record paper and thelike, a rotatable gear box supporting a gear train and carrying aplurality of paper engageable drive rollers circularly arrangedconcentrically about the gear box axis and respectively connected todifferent portions of the gear train, said gear box being rotatablethrough a plurality of adjusted positions in each of which positions oneof the drive rollers is in paper engageable position, indexing cam meansfor resiliently holding the gear box in each of said positions,disconnectable means for providing positive holding of the gear box ineach of said adjusted positions, a shaft for rotating the gear box,means connecting the shaft to the gear box for rotation therewith andfor axial movement relative to the gear box, means urging the shaftaxially in one direction, said disconnectable means being in partconnected to said shaft and being disconnectable in response to axialmovement of the shaft in the direction opposite said one direction.

9. In a variable speed mechanism for advancing record paper and thelike, a rotatably mounted gear box supporting a gear train and carryinga plurality of paper engageable drive rollers connected respectively todifferent portions of the gear train, said gear box being adjustablethrough a plurality of rotated positions in each of which positions oneof said rollers is in paper engageable position, means externally of thegear box to drive said gear train, a rotatable shaft extending coaxiallyof the gear box and movable axially relative to the gear box, meansproviding a driving connection between the shaft and gear box forrotation of the gear box by the shaft while permitting axial movement ofthe shaft relative to the gear box, means urging the shaft axially inone direction, a pressure roll mounted for movement toward and away fromsaid one of said rollers, means for moving the pressure roll away fromsaid one of said rollers in response to movement of said shaft in thedirection opposite said one direction including a cam on said shaft, thecam being provided with a plurality of recesses arranged about the axisof the shaft and corresponding respectively to said adjusted positionsof the gear box, and fixed shoulder means engageable in said recesses topositively hold the gear box in each of said adjusted positions, saidshoulder means being disengagea-ble for each recess in the cam uponmovement of the cam in the direction opposite said one direction ofshaft movement.

10. In a variable speed mechanism for advancing record paper and thelike, a gear box mounted for rotation about an axis and supporting agear train, a plurality of circularly arranged paper engageable driverollers carried by the gear box concentrically of the gear box axis andconnected respectively to different portions of the gear train, the gearbox being rotatable through a plurality of adjusted positions in each ofwhich positions one of said drive rollers is in paper engageableposition, a gear mounted for rotation coaxially of the gear box, meansto drive said gear, means drivingly connecting said gear to the geartrain including an idler gear rotatably carried by the gear box andmeshed with the first gear for rotation thereby about an axis extendingin spaced parallel relation to the axis of said first gear, a pressureroll mounted for movement toward and away from said one of said rollersfor firmly engaging a record paper with said one of said drive rollers,a shaft connected to the gear box for rotation thereof and for axialmovement relative thereto, means connected to the pressure roll andresponsive to axial movement of said shaft to move the pressure rollaway from said one of said drive rollers, and releasable means normallypreventing rotation of the gear box by said shaft, a portion of saidreleasable means being connected to said shaft to release the gear boxfor rotation in response to axial movement of the shaft.

11. In a variable speed mechanism for advancing record paper and thelike, a gear box mounted for rotation about an axis and supporting agear train, a plurality of circularly arranged paper engageable driverollers carried by the gear box concentrically of the gear box axis andconnected respectively to different portions of the gear train, the gearbox being rotatable through a plurality of adjusted positions in each ofwhich positions one of said drive rollers is in paper engageableposition, a gear mounted for rotation coaxially of the gear box, meansto drive said gear, means drivingly connecting said gear to the geartrain including an idler gear rotatably carried by the gear box andmeshed with the first gear for rotation thereby about an axis extendingin spaced parallel relation to the axis of said first gear, a pressureroll mounted for movement toward and away from said one of said rollersfor firmly engaging a record paper with said one of said drive rollers,a shaft connected to the gear box for rotation thereof and for axialmovement relative thereto, a cam carried by said shaft for rotative andaxial movement therewith, follower means connecting the cam and pressureroll to provide for movement of the pressure roll away from said one ofsaid drive rollers in response to axial movement of the shaft in onedirection, a spring urging the shaft in a direction opposite said onedirection, a plurality of recesses in said cam circularly arrangedcoaxially of the shaft and corresponding respectively to said adjustedpositions of the gear box, and a fixed member engageable in saidrecesses to hold said shaft and cam against rotation in a positioncorresponding to a selected adjusted position of the gear box and beingdisengageable from the cam in response to axial movement of the shaft insaid one direction.

12. In a variable speed mechanism for advancing record paper and thelike, a rotatably mounted gear box supporting a gear train and carryinga plurality of paper engageable drive rollers arranged about the axis ofthe gear box and connected respectively to different portions of thegear train, said gear box being rotatable through a plurality ofadjusted positions in each of which positions one of said rollers is inpaper engageable position, a pressure roll engageable with the oppositeside of paper engaged by said one of said rollers, means mounting thepressure roll for movement toward and away from said one of saidrollers, means urging the pressure roll toward said one of said rollers,and means to sequentially move the pressure roll away from said selectedone of said rollers and rotate said gear box including a rotatableshaft, said means being operable to initiate movement of the pressureroll away from said selected one of said rollers in response to initialrotation of said shaft.

13. In a variable speed mechanism for advancing record paper and thelike, a rotatably mounted gear box supporting a gear train and carryinga plurality of paper engageable drive rollers arranged about the axis ofthe gear box and connected respectively to different portions of thegear train, said gear box being rotatable through a plurality ofadjusted positions in each of which positions one of said rollers is inpaper engageable position, a pressure roll engageable with the oppositeside of paper engaged by said one of said rollers, means mounting thepressure roll for movement toward and away from said one of saidrollers, means urging the pressure roll toward said one of said rollers,means to move said pressure roll away from said selected one of saidrollers including a rotatable member, and a lost motion drivingconnection between said rotatable member and the gear box.

14. In a variable speed mechanism for advancing record paper and thelike, a rotatably mounted gear box supporting a gear train and carryinga plurality of paper engageable drive rollers arranged about the axis ofthe gear box and connected respectively to different portions of thegear train, said gear box being rotatable through a plurality ofadjusted positions in each of which positions one of said rollers is inpaper engageable position, a pressure roll engageable with the oppositeside of paper engaged by said one of said rollers, means mounting thepressure roll for movement toward and away from said one of saidrollers, means urging the pressure roll toward said one of said rollers,means to move said pressure roll away from said selected one of saidrollers including a rotatable cam and a movable cam follower, meansreleasably holding the gear box in selected angularly adjusted positionincluding a locking member mounted for rotation with the gear box andhaving a plurality of recesses angularly spaced about the gear box axisand corresponding in number and angular spacing to that of said rollers,a member movable into and out of said recesses, and a lost motiondriving connection between said cam and locking member.

15. In a variable speed mechanism for advancing record paper and thelike, a gear box mounted for rotation about an axis and supporting agear train, a plurality of circularly arranged paper engageable driverollers carried by the gear box concentrically of the gear box axis andconnected respectively to difierent portions of the gear train, the gearbox being rotatable through a plurality of adjusted positions in each ofwhich positions one of said drive rollers is in paper engageableposition, a gear mounted for rotation coaxially of the gear box, meansdrivingly connecting said gear to the gear train including an idler gearrotatably carried by the gear box and meshed with the first gear forrotation thereby about an axis extending in spaced parallel relation tothe axis of said first gear, a pressure roll mounted for movement towardand away from said one of said rollers for firmly engaging a recordpaper with said one of said drive rollers, a shaft extending coaxiallyof the gear box, said shaft being rotatable relative to the gear box, acam mounted on said shaft for rotation therewith, said cam having aseries of valleys and promontories arranged about the axis of saidshaft, a follower engageable with said promontories and valleys andoperatively connected to said pressure roll to move the same in responseto rotation of the cam to move the follower out of one ofsaid valleys,said valleys corresponding in num- References Cited in the file of thispatent UNITED STATES PATENTS 2,642,756 Cummings June 23, 1953 a ---r Al,

